- pool.go: add missing Arena.Reset() call inside ArenaPool.Put()
- Treat nil values as null in SetArrayItem
prevents a potential panic when a nil value is used as an array item
full diff: https://github.com/valyala/fastjson/compare/v1.6.4...v1.6.7
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>